What is an EVSE and why do we care?

What is the device shown in the photograph at right? My quick answer, and you might say the same thing, is that it is “an EV charger”. But my quick answer is wrong. The device shown at right is a mere “EVSE”, not an “EV charger”. This fact, it turns out, explains why a Hyundai Kona charges at a mere 26 miles per hour, when plugged into this 48-amp device, instead of as much as 42 or 43 miles per hour the way some other EV might do.   See a blog article about this.